JP4226973B2 - X-ray crystal orientation measuring apparatus with crystal sample holding device - Google Patents

Description

  The present invention relates to a crystal orientation cutting method for cutting a crystal such as a single crystal material in a predetermined crystal orientation, and further, a crystal sample holding device used for carrying out such a method and an X-ray crystal suitable for it. The present invention relates to an azimuth measuring device.

  In general, a single crystal is a regular periodic arrangement of atoms or molecules, and therefore the crystal orientation is the same everywhere in the crystal, and such a crystal is usually said to be single domain. Is called. In such a single crystal, mechanical, optical, and electromagnetic properties are different depending on the crystal orientation (there is anisotropy). When actively utilizing the characteristics of this crystal, the crystal orientation is investigated, It is cut out in a certain direction (fixed orientation cutting) and used. Therefore, crystal orientation measurement is required.

By the way, the crystal orientation measurement method in the prior art will be described below with reference to the accompanying drawings.
First, FIG. 8 shows a first example (direction measuring method using a goniostat and a polaroid cassette ( Polaroid is a registered trademark)) . In this example, the following procedure is performed in order to perform a fixed-direction cutting process.
( 1 ) The crystal is fixed on a goniostat having a three-axis rotation mechanism orthogonal to each other. (2) Take a Laue photo with Polaroid cassette. (3) Analyzing the imaging result, adjusting the angle to a desired lattice plane by correcting the angle by rotating around three axes. (4) After adjustment, photographing is performed to confirm whether a predetermined lattice plane is set. Make fine adjustments if necessary. (5) Transfer the crystal together with the goniostat to the outer peripheral tooth cutter and cut the crystal.

  This method is the most commonly performed method, however, the maximum diameter of the crystal that can be handled is up to about 20 mm. For example, a huge crystal of meteorite (for example, a large diameter of 300 to 400 mm). It is not possible to apply it to the crystal.

Next, in the example shown in FIG. 9 (an orientation measurement method using a three-axis rotation mechanism and a Polaroid cassette (Polaroid is a registered trademark)) , the crystal is held by the orthogonal three-axis rotation mechanism. Can be adjusted. In this example, the crystals that are used for the inner peripheral tooth cutter and have been chamfered by adjusting the orientation are transferred to the cutter vise together with the φ rotation mechanism. After that, the χ and ω angles are read with a goniometer scale plate, copied to the χ and ω rotating mechanism attached to the cutter, and cut. However, the size of the crystals that can be handled by this method is at most about 100 mm in diameter, and cannot be applied to the above-mentioned huge meteorite crystals.

  Furthermore, the attached example of FIG. 10 is a method that can be applied to a giant crystal as described above. However, since the crystal is huge and heavy, the χ rotation mechanism must be omitted. Therefore, surface adjustment is performed exclusively by the φ and ω rotating mechanisms. By the way, in order to place the crystal in the V-groove of the goniometer, it is necessary to maintain the outer shape of the crystal that is cylindrically ground and that both end faces are cut perpendicular to the rod axis. The ω rotation can set the crystal on the V-groove by adjusting the rotary knob, while the φ rotation uses a protractor (protractor).

First, a reference marking line is put on the outer peripheral surface of the crystal before photographing with a Polaroid cassette (Polaroid is a registered trademark) . After the orientation measurement, the protractor is set to an angle that should be corrected for rotation, and the crystal is rotated so that the set ruler and the marking line are parallel. Return the protractor to the zero position, write the marking line again, and use this as the reference line for cutting. In this case, since the outer peripheral teeth and the inner peripheral teeth cannot be used as the cutter, the crystal is cut with a band saw cutter. After that, set it in parallel with the marking line of φ rotation position with a skewer. Set the end face and cutter blade to ω angle and cut. I followed the above steps.

In addition, for example, in the meteorite crystal (CaF ₂ , Fluorite) grown by the Bridgeman method, in recent years, a crystal having a large diameter of 300 to 400 mm has been artificially grown in order to fulfill various application purposes. As described above, when the anisotropy due to the crystal orientation is positively utilized, it is necessary to investigate the orientation of such a huge crystal and cut it in a necessary orientation. .

  In addition, crystal orientation measurement is to examine how the crystal axes are attached to the outer shape of the crystal (all three-axis orientations). For this purpose, the Laue method is generally used. It's being used.

  Furthermore, according to Patent Document 1 shown below, there is also a method and apparatus for measuring an incident angle of X-rays at which Bragg reflection occurs using characteristic X-rays, and measuring a plane orientation obtained from a known Bragg angle. Already known. In addition, the plane orientation measuring apparatus which employ | adopted this measuring method is already commercialized, for example, is commercialized by the name of FSAS or SAM.

  Also, the crystal orientation is measured by measuring the incident angle of X-rays where Bragg reflection occurs, using characteristic X-rays, and also investigating where the diffracted X-rays are incident. The method of doing this is already known from Patent Document 2 below.

Japanese Examined Patent Publication No. 4-59581 (Japanese Patent Laid-Open No. 57-136151); FIG. Japanese Examined Patent Publication No. 3-58058 (JP-A 57-136150); FIG.

  Although some of the conventional techniques described above can handle large crystals, there are disadvantages, however, that preparations such as cylindrical grinding of the crystal and machining of the end face perpendicular to the rod axis are time-consuming. It was. In particular, the meteorite crystal is grown by the Bridgman method. Therefore, the shape after the crystal growth is usually a crucible shape, so-called a cylindrical portion and a conical portion. Such huge crystals of meteorites are very expensive crystals that require high power and a long time (about 3 months) for crystal growth. For this reason, there is a strong demand not to use the cone part as much as possible.

  In addition, a feature of the meteorite is that it has a so-called subgrain structure composed of crystal grains having slightly different orientations. However, in the above-described X-ray azimuth measurement sample holding mechanism described above, it is difficult or more complicated when it is attempted to carry out a constant azimuth cutting process with an average value by measuring several places. It was something that required a mechanism.

  Therefore, the present invention solves the above-mentioned problems in the prior art, and in particular, is a method for measuring the crystal orientation of a huge crystal such as a meteorite crystal and cutting it out at a desired constant orientation. A crystal orientation cutting method that can be realized, and an X-ray crystal orientation measuring apparatus suitable for use in measuring the crystal orientation in such a crystal orientation cutting method are provided. An object is to provide a crystal sample holding device suitable for use.

  In order to achieve the above object, according to the present invention, first, a measurement table is formed in a part thereof, a sample table that can be placed with a measured surface of a crystal sample as a lower surface, and a lower portion of the table. And means for irradiating the measurement surface of the crystal sample with the X-rays through the small holes for measurement, means for imaging a diffraction image from the measurement surface of the crystal sample, and imaging by the imaging means An X-ray crystal orientation measuring apparatus for measuring the crystal orientation on the surface to be measured of the crystal sample is provided based on the diffraction image.

  Moreover, according to the present invention, the above-described X-ray crystal orientation measuring apparatus may further include means for allowing the crystal sample placed on the sample table to move on the surface thereof, The means for capturing a diffraction image from the surface to be measured of the crystal sample is preferably constituted by a CCD camera.

  Furthermore, according to the present invention, in order to achieve the above object, there is also provided a crystal sample holding device used for measuring the crystal orientation of a crystal sample by the X-ray crystal orientation measuring device described above, A sample table in which a small hole for measurement is partially formed and having a smooth surface, and a sheet shape that is disposed on the smooth surface of the sample table and can transmit X-rays to the bottom surface of a frame of a predetermined shape There is provided a crystal sample holding device comprising a sample holder part to which a member is attached and a moving means for allowing the sample holder part to move on a smooth surface of the sample table.

In the present invention, in the crystal sample holding device, the smooth surface of the sample table is formed of engineering plastic, and / or the sheet-like member that can transmit X-rays is a PET sheet or a Lumirror sheet ( Lumirror is preferably composed of registered trademark . In addition, it is preferable that a mark for determining the position of the crystal sample placed thereon is formed on the surface of the permeable sheet-like member.

  Furthermore, according to the present invention, there is also provided a crystal orientation cutting method for measuring a crystal orientation of a crystal body and cutting the crystal body in a predetermined orientation in order to achieve the above object. A crystal in which a part is cut out, the crystal orientation at the cut surface of the cut out crystal is measured by the X-ray crystal orientation measuring apparatus described above, and the crystal is cut along a predetermined crystal orientation according to the measurement result A fixed-direction cutting method is provided.

  And according to the present invention, in the crystal orientation cutting method, the step may be repeated to finely adjust the cut surface, or when measuring the crystal orientation in the cut surface of the cut crystal The crystal orientation at a plurality of points may be measured while moving the cut crystal.

  According to the crystal sample holding device and the X-ray crystal orientation measuring device according to the present invention, the crystal orientation analysis of a large-diameter crystal sample can be easily and easily performed. By using this apparatus, it is possible to exhibit an excellent effect that a measurement sample including a giant crystal can be cut without waste and in an accurate orientation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, a crystal sample holding device according to the present invention will be described with reference to FIGS. This crystal sample holding device is configured as a so-called sample stage in which a huge crystal such as the above-mentioned meteorite crystal can be placed on its reference plane and moved on a plane (xy axis).

The sample stage has the following structure and function.
First, as shown in FIG. 2, in this sample stage, a sample holder 20 is arranged on a sample table 10 of a flat plate, and the sample holder 20 is moved in the x-axis and y-axis directions on the sample table plane. Possible X and Y moving mechanisms 30 and 40 are provided. Although not shown here, a small hole for measuring the crystal orientation of the sample is formed in the center of the sample table 10 (intersection of marking lines described below).

Further, as shown in FIGS. 3A and 3B, the sample holder 20 on which the sample (sample) S is placed has, for example, an outer shape of 530 mm × 550 mm and an opening in the so-called “Robot”. It has a structure in which a transparent film 22 is stretched on a metal frame 21 having a letter "". Incidentally, the transparent film 22 is, for example, PET sheets and Le mirror sheet (Lumirror registered trademark), a transparent sheet which transmits X-ray, the sheet can, for example, adhering to the rear face of the metal frame 21 It is attached with double-sided tape to form a sample holding surface. On the other hand, the sample table 10 is formed of a so-called engineering plastic plate made of a polymer material having a small friction on the surface thereof, and forms a smooth surface. Reference numeral 23 in the figure denotes a reference cross mark formed in a cross shape on the transparent sheet 22 at the center of the sample holder 20, a so-called marking line.

  Returning to FIG. 2 again, the sample holder 20 moves in a state where the sample (S), which is a huge crystal such as a meteorite crystal, is placed on the center portion thereof. A transparent film (sheet) 22 attached to the back surface of 20 with a double-sided tape is supported and moved on an engineering plastic plate with a small friction on the surface. The mechanism 30 or 40 can be moved freely. In the present embodiment, the X and Y moving mechanisms 30 and 40 are each constituted by a guide rail and a screw feed, and reference numerals 31 and 41 in the drawing respectively rotate the screw feed. Is the handle. Further, the display on the X and Y axes is performed in units of mm, for example, and display by LEDs and scale display are also possible. Furthermore, instead of the moving mechanism by the handle operation described above, an electric moving mechanism by a stepping motor can be adopted.

  Further, in the sample stage having the above-described configuration, the sample S is simply placed on the transparent sheet 22 of the sample holder 20 with its surface to be measured facing down, and is not clamped, and the frictional force with the transparent sheet. Therefore, it does not have any adverse effect on the measurement of the crystal orientation on the surface to be measured, and is a structure suitable as a crystal holding mechanism for orientation measurement.

The sample S mounted on the sample stage is particularly a huge crystal such as a meteorite crystal, and the sample size is about 450 mm in maximum diameter, 300 mm in maximum thickness, and 150 kg in maximum weight. The conditions of the sample whose crystal orientation can be measured by the X-ray crystal orientation measuring apparatus of the present invention described later include the following from the characteristics of the sample stage that is the crystal sample holding apparatus described above.
(1) Since the measurement surface is held only on the reference surface, the measurement surface should be flat without unevenness.
(2) The shape of the sample is not limited as long as the measurement surface is flat even if it is cylindrical, conical, or slab-shaped.
(3) As a reference for azimuth analysis, an azimuth line is attached to the side surface of the sample to make it a sample reference.
(4) The finish of the measurement surface should be able to observe Laue spots. In other words, the processing strain is such that it does not affect the measurement. Usually, an AsCut surface with diamond blades is sufficient.

  Next, with respect to the configuration of the X-ray crystal orientation measuring apparatus for measuring the crystal orientation of the sample S held so as to be movable in the xy axis direction by the crystal sample holding apparatus (sample stage) described above, FIG. Will be described with reference to FIG.

  As clearly shown in FIG. 4, a small hole (for measurement) for measuring the crystal orientation of the sample formed in the central portion of the sample table 10 described above is indicated by reference numeral 11. As shown in the figure, the small hole 11 is formed in a so-called tapered shape having a small opening diameter on its upper surface but expanding toward its bottom surface. An X-ray tube 100 for generating X-rays for measurement, and X-rays for measurement from the X-ray tube 100 are made parallel X-rays at a predetermined diameter below the measurement small hole 11. A collimator 110 for narrowing down and a so-called CCD camera 120 which is an apparatus for imaging a Laue pattern obtained by irradiating the lower surface (measurement surface) of the X-ray with the X-ray is provided. Yes. Reference numeral 101 in the figure denotes a so-called X-ray generator provided with means for supplying a predetermined high voltage or the like to the X-ray tube 100.

  As shown in FIG. 4, the collimator 110 is set and arranged so as to be incident on the lower surface (measurement surface) of the sample crystal S at a predetermined angle ω (for example, about 60 degrees). On the other hand, the CCD camera 120 for imaging the Laue pattern is also arranged at the same angle ω with respect to the lower surface (measurement surface) of the sample crystal S. In addition, a fluorescent screen 121 that generates light by irradiated X-rays is attached to the front surface of the CCD camera 120, and the CCD camera 120 images a Laue pattern formed by the light emission of the fluorescent screen 121 and generates an electrical signal. Convert. The distance between the fluorescent plate 121 and the lower surface (measurement surface) of the sample crystal S is set to about 35 mm, for example.

  The CCD camera 120 has a camera control 122 for performing the control, and an image grabber 123 for performing a digital process on the image signal obtained by the CCD camera 120 and loading it into the memory of the CPU. It is connected. The camera control 122 and the image grabber 123 are connected to a CPU 140 that is a control device (for example, configured from a personal computer). The CPU 140 includes a display 141 that is an output device and an input device. A keyboard 142 and a mouse 143 as a pointing device are connected to a hard disk device (HD) 144 as a storage means, a CD-ROM 145 and an FD 146, and a printer 147 as an output device.

  According to the X-ray crystal orientation measuring apparatus whose configuration has been described above, the sample S as the measurement crystal is simply placed on the sample stage (see FIG. 2) as the crystal sample holding apparatus. That is, while moving with the sample S placed on the sample stage which is the crystal sample holding device, the crystal orientation on the measurement surface on the lower surface is measured by the function of the X-ray crystal orientation measuring device. That is, the X-rays generated from the X-ray tube 100 are focused by the collimator 110 and irradiated on the lower surface of the sample S. The resulting Laue pattern is projected onto the fluorescent screen 121 and imaged by the CCD camera 120. Thereafter, the image captured by the CPU 140 is subjected to, for example, image processing by a software program or the like stored in the HD 144, the Laue spot position is measured, and all three-axis orientation analysis is automatically executed.

  Subsequently, the crystal orientation of a single crystal material such as meteorite is measured and cut in a predetermined orientation by the X-ray crystal orientation measuring device and the crystal sample holding device (sample stage) described in detail above. The crystal orientation cutting method will be described with reference to FIG. In the following description, as described above, a so-called crucible-shaped meteorite crystal or the like having a maximum diameter of 450 mm, a weight of about 200 to 3000 kg, and a cone portion stacked on the cylindrical portion, etc. A fixed orientation cutting method that cuts out a huge crystal in a predetermined direction will be described.

  First, as shown by a broken line in FIG. 1A, a cone portion (a part of the tip) c1 is cut from a crucible-shaped crystal C. At that time, a reference line r is placed at the cutting point so that the relationship between the crystallized crystal body and the crystal body can be understood (for example, an orthogonal direction on a plane perpendicular to the axial direction).

  Next, as shown in FIG. 1B, the orientation of the cut surface of the cut-out cone part c1 is measured. That is, the inclination angle α and the inclination direction β of the lattice plane to be cut in a fixed orientation are obtained. If necessary, the crystal sample holding device (sample stage) is used to move the lower surface of the cone c1 in the X-Y axis direction, measure the orientation at a plurality of points in the crystal plane, and α, β can also be given.

  The inclination angle α and direction β are used as a reference for attaching the azimuth line a. The relationship between the vector V obtained as a result of the azimuth measurement, the xy axis (four azimuth lines a), and the inclination angle α of the lattice plane and the inclination direction β is shown in FIG. That is, in order to express the orientation of the lattice plane in FIG. 5, the azimuth angles α and β are defined with respect to the reference coordinates (xyz) of the orientation analysis shown in FIG. The angle α is an angle formed by the lattice plane normal line and the z axis, and the angle β is an angle formed by the projection line of the lattice plane method green onto the xy plane and the x axis. In this way, the inclination angle α of the lattice plane and the direction angle β of the inclination with respect to the outer shape of the crystal can be understood from the result of the above analysis. Then, as shown in FIG. 6, the cone portion and the crystal body are aligned with a reference line, the azimuth line is copied to the crystal body, xy coordinates are determined, and angles α and β are set based on the xy coordinates. Cut (FIG. 1C).

  Further details of the above-described method of cutting the fixed orientation will be described. For example, when it is desired to cut out by adjusting the plane orientation to {111}, α is selected as the smallest value among {111} from the result of orientation measurement. For example, in the example of the result of all three-axis azimuth measurements shown in FIG. 7 attached, α of (−1-11) indicated by an underline indicates the smallest value. Here, the reason why the small value of α is selected is to facilitate cutting and minimize waste of material (by being shaped into a cylindrical shape). And this cutting | disconnection cuts with a cutter, setting (alpha) and (beta) angle | corner as shown in attached FIG. 6 on the basis of the azimuth line a ((x, y) coordinate). In the above description, the method of cutting the azimuth direction is described in the case of a cylindrical shape for the sake of simplicity. However, in practice, it is desirable to perform the procedure according to the procedure shown in FIG.

  Furthermore, orientation measurement is performed with the cut surface of the slab-like crystal c2 cut in FIG. 1C (see FIG. 1D), and it is confirmed whether or not it is cut in a desired direction. As a result, if correction is necessary, the above-described operation shown in FIG. 1C is repeated to finely adjust the cut surface. Then, if the crystal body C is cut with a predetermined orientation accuracy, the crystal body C is then cut with a necessary thickness on the basis of the cut surface (so-called main cutting is performed), and the desired anisotropy is provided. A cylindrical (disk) crystal is obtained. At this time, when the crystal sample is placed on the center portion of the sample holder 20, the azimuth line attached to the sample side is aligned with the cross mark (reference cross) formed on the transparent sheet 22 of the sample holder 20. Arrange as follows. Or after putting a sample, you may attach an azimuth line according to a reference cross.

  When performing orientation measurement in the steps shown in FIGS. 1B and 1D, particularly in the case of a huge crystal as described above, the cut crystal (sample S) also becomes a large weight crystal. According to the crystal sample holding apparatus (sample stage) as described above, for example, a fluorite crystal of 400 mmφ, 100 mm thickness and about 40 kg can be moved in the XY direction, and the orientation can be measured with high accuracy. I can do it. Further, when handling a weight crystal, for example, a sample S which is a huge crystal such as a meteorite crystal and whose sample size has a maximum diameter of 450 mm, a maximum thickness of 300 mm, and a maximum weight of about 150 kg is used. This is possible by introducing compressed air between the sample table 10 and the transparent sheet 22 to be configured, and performing the XY movement of the sample with air. However, this is not necessary when measuring azimuth, and levitation by air is stopped.

In addition, in the example of the above-described embodiment, as shown in FIG. 4, the method using the side reflection Laue optical system using the CCD is shown. However, the present invention is limited to this. In addition, for example, it is also possible to measure with a back reflection Laue method optical system based on a polaroid photograph (Polaroid is a registered trademark) .

  As described above, according to the invention, it is possible to measure the crystal orientation while moving the sample crystal simply by placing the sample crystal for measuring the crystal orientation on the sample stage of the sample table with the measurement surface facing downward. Become. In particular, the above-mentioned huge crystals such as meteorites may have a sub-grain structure in some of them, and by measuring several points in the sample surface, the angle of the fixed orientation cut is determined by the average of the measurement results There is. Even in such a case, according to the crystal sample holding device (sample stage), since the sample crystal is only placed on the sample stage, the sample is moved so that the posture of the sample does not change every measurement, and The sample can be prevented from being stressed by a clamp or the like, and high-precision azimuth measurement can be performed in a good state.

Industrial availability

  As is clear from the above detailed description, according to the crystal sample holding device and the X-ray crystal orientation measuring device according to the present invention, crystal orientation analysis of a large-diameter crystal sample can be easily and easily performed, and In the crystal orientation cutting method according to the present invention, by using these devices, an excellent effect is achieved that it is possible to cut a measurement sample including a giant crystal without waste and in an accurate orientation. It can be applied to a crystal sample holding device and an X-ray crystal orientation measuring device.

It is explanatory drawing explaining the process in the crystal orientation cutting method which becomes one embodiment of this invention. It is a top view which shows the whole structure of the crystal sample holding | maintenance apparatus (sample stage) used for the said crystal orientation cutting method. It is the expansion | deployment perspective view which shows the detailed structure of the sample holder of the said crystal | crystallization sample holding device (sample stage), and its back view. It is a figure which shows the whole structure of the X-ray crystal orientation measuring apparatus used for the said crystal orientation cutting method. FIG. 6 is a diagram for explaining the relationship between the lattice plane tilt angle α and the direction β, the lattice plane normal vector, and the xy axes (four azimuth lines) in the crystal orientation cutting method. It is a figure explaining the cut surface cut | disconnected in the said crystal orientation cutting method. In the said crystal orientation cutting method, it is a figure which shows an example of the result of all the triaxial orientation measurement by the said X-ray crystal orientation measuring apparatus. It is a figure which shows an example (direction measuring method using a goniostat and a polaroid cassette (Polaroid is a registered trademark)) of a prior art. It is a figure which shows the other example (direction measuring method using a 3 axis | shaft rotation mechanism and a Polaroid cassette (Polaroid is a registered trademark)) of a prior art. It is a figure which shows the further another example of a prior art.

Explanation of symbols

10 Sample table 11 Small hole for measurement 20 Sample holder 21 Gold frame 22 Transparent sheet 23 Reference cross mark (marking line)
30, 40 X, Y moving mechanism 100 X-ray tube 110 Collimator 120 CCD camera 121 Fluorescent plate S Sample C Crystal body c1 Cutting weight c2 Cut slab crystal

Claims (4)

A small hole for measurement is formed in a part of the sample table, and is arranged on the smooth surface of a sample table having a smooth surface. And a sample holder part for placing the surface to be measured of the crystal sample on the permeable sheet-like member, and a movement for allowing the sample holder part to move on the smooth surface of the sample table. A crystal sample holding device having means,
Means for irradiating the measurement surface of the crystal sample with X-rays through the small holes for measurement, and means for imaging a diffraction image from the measurement surface of the crystal sample; X-ray crystal orientation measurement provided with a crystal sample holding device, comprising: means for measuring a crystal orientation on a surface to be measured of the crystal sample based on a diffraction image picked up by the image pickup means apparatus.   2. An X-ray crystal orientation measuring apparatus comprising the crystal sample holding apparatus according to claim 1, wherein the smooth surface of the sample table is formed of an engineering plastic. Orientation measuring device. 2. An X-ray crystal orientation measuring apparatus comprising the crystal sample holding apparatus according to claim 1, wherein the transmissive sheet-like member is made of a PET sheet . X-ray crystal orientation measuring device.   4. An X-ray crystal orientation measuring device comprising the crystal sample holding device according to claim 3, wherein the surface of the permeable sheet-like member is used to determine the position of a crystal sample placed thereon. An X-ray crystal orientation measuring device provided with a crystal sample holding device, wherein a mark is formed.

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